HIV-affected adolescents and young adults (AYA) in sub-Saharan Africa (SSA) experience stressors that increase their risk for problematic alcohol use, which in turn can lead to HIV infection or transmission and poor HIV outcomes, including linkage to care and ART adherence. Efforts to address the HIV epidemic among adolescents and young adults in SSA have therefore focused, in part, on treating risky alcohol use. Yet, the vast majority of HIV-affected AYA in SSA who need alcohol services do not receive them, resulting in a substantial treatment gap. A critical barrier to the accurate screening for risky alcohol use among AYA and provision of appropriate treatment is a lack of objective measures for alcohol consumption in HIV care settings, which rely primarily on self-report alone. This K01 mentored research scientist development proposal aims to examine the role of biomarkers in improving alcohol screening and treatment referral among AYA in HIV prevention and treatment clinics. Specifically, the proposal will investigate a urine-based biomarker, ethyl glucuronide (UEtG), which has displayed potential as a point-of-care diagnostic tool among clinic-based populations in the U.S. but has not been investigated as a valid and feasible method within HIV care settings among AYA. Research activities for this proposal will take place in Zambia, a country with one of the highest HIV prevalence estimates in the world. The research will leverage over a decade of HIV research in Zambia by Johns Hopkins University and a longstanding collaboration with Centre for Infectious Disease Research in Zambia (CIDRZ), the local implementing partner. Specific aims of the proposal are to: 1) assess the test characteristics of UEtG among HIV-affected AYA in Zambia; 2) develop a protocol for the use of rapid UEtG dip card testing embedded within AYA HIV prevention and treatment; and 3) pilot the UEtG protocol developed in Aim 2 and refine procedures with a formative evaluation process. Findings will inform implementation strategies that can be tested in a follow-up study. The research is designed to be an integral component of a rigorous training and career development plan focused on HIV/AIDS, alcohol biomarkers, and implementation science. Training will take the form of coursework, lab training, and one-on-one mentorship with an experienced and dedicated team of multidisciplinary mentors and consultants who are widely considered to be experts in their respective fields. The goal of the professional development plan is to facilitate the candidate's transition into an independent investigator in alcohol epidemiology and implementation science with specific expertise in HIV and biomarkers. The proposal is directly in line with Goal 2 (?improve diagnosis and tracking of alcohol misuse?) and Objective 5c (?facilitating dissemination and implementation of evidence-based practices for diagnosing alcohol misuse?) of the NIAAA Strategic plan 2017-2021. The proposal is consistent with NIH high priority HIV research in addressing ?health disparities in the incidence of new HIV infections? and ?research training of the workforce required to conduct high priority HIV/AIDS or HIV/AIDS-related research.?